Impedance controlling apparatus



July 12, 1938. o. 1-. HANDWERK IMPEDANCE CONTROLLING APPARATUS s Sheets-Sheet 1 Filed April 23, 1936 [72 verzzaz Otto TAvzdwen/a 7110 W 9- M A zor megs July 12, 1938 Q HANDWERK 2,123,725

IMPEDANCE CONTROLLING APPARATUS Filed April 23, 1936 3 Sheets-Sheet 2 [nz/ezzzfor Aft 2 2zey5 July 12, 1938. o.' T. HANDWERK IMPEDANCE CONTROLLING APPARATUS 3 Sheets-Sheet 3 Filed April 23, 1936 fizz/22222 0/60 Z'Ha'rzau/enk 5 712:: A m

I Patented July 12, 1938 UNITED STATES PATENT OFFICE out T. Handwerk, Chicago, 111., assignor to Republic Flow Meters Company, Chicago, 111., a

corporation of Illinois Application April 23, 1936, Serial No. 76,013

9 Claims.

This invention relates to measuring apparatus,

and is illustrated as embodied in an apparatus for integrating a flow measurement with a differential temperature measurement to find the 5 quantity of heat absorbed or given up by the fluid stream being measured, as for example the quantity of heat absorbed by the cooling coil of a refrigerator system.

In one desirable arrangement a flow-controlled resistance or other reactance, such as a standard electrically-registering flow-meter, is arranged in an indicator circuit in series with a variable impedance (as for example a variable-step transformer) controlled in accordance with the differential temperature measurement. However, many of the features and advantageous arrangements described below are applicable to circuits controlled by other conditions than flow and temperature.

An important feature of the invention relates to increasing the sensitivity and accuracy of the apparatus, by arranging the variable impedance for operation by power derived from a reversible, electric motor controlled in accordance with the particular condition which it is desired should vary the setting of the impedance. Preferably the motor runs continuously, in one direction or the other, and the setting of the impedance is determined by constantly reversing the motor 30 about the desired settingas a neutral point. If desired, the motor may drive the impedance through a-lost-motion connection, so that the setting is only actually changed by the motor when the value of the controlling condition changes.

The mechanism for controlling the reversal of the motor, under the control of the measured condition, in itself embodies substantial novelty. In the illustrated embodiment of the invention,

' the controlling measurement is utilized to set a variably-positioned stop, as for example a. vertical link having a control slot in its end, which cooperates with a device which is shifted constantly back andforth by the motor, automatically to open and close contacts in a control circuit, which operates (by a solenold or the like) a reversing switchwhich in turn controls the operation of the motor.

The above and other objects and features of the invention, including various novel combinations of parts and desirable particular constructions, will be apparent from the following description of the illustrative embodiment shown in-the accompanying drawings, in which:

Figure 1 is a diagrammatic perspective of the variable impedance and the means for controlling it according to a diiierential pressure measurement;

' Figures 2 and 3 are perspective views of devices capable of use for controlling the variable impedance according to other conditions than differential temperature;

Figures 4 and 5 are diagrams showing the switch-controlling means of the apparatus in difierent positions;

Figure 6 is a wiring diagram showing the apparatus of Figure 1 in an indicator circuit which also includes a standard electric flow-meter;

Figure 7 is a perspective view of a lost-motion mechanism which may be used to connect the motor and the variable impedance; and

Figures 8, 9, 10,-and 11 are diagrams showing the use of different cams according to diiIerent ranges of temperature differentials to be measured. 20

'The apparatus illustrated is intended, as one of its uses, for connection in a circuit such as that illustrated in Figure 6. This particular circuit includes a source of electric power such as a transformer I0 the primary of which is connected into the usual lighting circuit l2, and the secondary of which is connected by a line H to one terminalof a standard electric flowmeter l6 arranged, for example, to measure the flow of brine or the like through a refrigerating system. This flow-meter may, if desired, be constructed substantially as described in Patents Nos. 1,390,394 and 1,601,743, granted September 13, 1921, and October 5, 1926, respectively.

As such flow-meters are well known commer- "35 cially, it is not necessary to describe them in detail, or further than to note that they produce a resistance to the flow of an electric current which is proportional to the flow being measured. Such a flow meter may therefore be'regarded broadly as a representative form of flow-controlled impedance.

The other'side of the flow-meter I6 is shown connected by a line II to a suitable electrical indicating device 20 which may, if desired, be of the type fully described in application No. 714,- 059, filed March 5, 1934, by Albert F. Spitzglass.

The indicator is connected by a line 22 to an adjustable arm 24 carrying the wiper 26 of a variable impedance such as a standard variable '50 step auto-transformer 28. The wiper 26 movably engages the coil 36 of the transformer, which coil has its primary terminals connected through lines 22 and 34 to the secondary terminals of the transformer l0.

to correspond to the difference in temperature between two points in a fluid stream whose flow is measured by the meter I0, as for example the intake and outlet ends ofa refrigerator coll, it will be seen that the temperature difi'erential is integrated with the now measurement to give a product indicated on the indicating instrument.

This product will be in proportion to the heat absorbed (or given up) between the two points at which the temperature measurements are made, and the instrument 20 can therefore be calibrated to read directly (for example) in British thermal units. I

The variable step auto-transformer 28 has its arm 24 mounted, as shown in Figure 'I, loosely on a central shaft 38, on which is fixed a second arm 40 having at its end a relatively wide notch embracing a drive pin 42 on the arm 20. This provides a lost-motion connection between the shaft 00 and the arm 20 such that the shaft 30 may oscillate constantly back and forth, without aifecting the position of the arm 24 except when the range of oscillation of the shaft 38 changes.

The shaft 38 carries a relatively large gear 00, shown as driven by an intermediate gear 40 from a pinion 48 driven by a reversible motor 00. The

motor 00 has two fields 52 and 50, and is continuously driven in one direction or the other according to which of the fields is energized. A lead 50 from one side of the transformer secondary connects with a leaf spring 50 carrying contacts on both sides, and forming the movable element of a reversing switch whichcontrols the motor.

When the leaf spring contact 00 is swungto the left, as shown in Figures 1 and 6, it engages a second leaf spring 00 connected through a lead 02 with the field 52 of the motor 00. The other side of the field 02 is connected through a lead 00 with one contact of a limit or safety switch 00 which in turn is connected through leads 00 and 00 with a line I2 connected to the other side of the secondary of the transformer I0. It will be noted that the above-described circuit (as well as the one through field 00 described below) is in parallel with the circult'through the fiowmeter I0 and the indicator 20.

When the leaf-spring contact 00 is swung to the right, it engages a third spring contact 00 connected by a lead It to the field 50. The field 06 at its opposite end is connected by a lead I0 to a second limit or safety switch 00, which is connected by a lead 02 and the above-mentioned lead I0 to the line I2.

The safety switches 00 and 00 are provided with operating levers 20, one or the other of which is engaged and operated by an arm 00 when and if the arm 20 (and therefore the gear 00) passes beyond its desired range of movement. For convenience the arm 00 is shown mounted on the gear 40, the limit switches 00 and 00 being adjustably mounted wherever desired about the periphery of the gear 06.

The spring contact 00 is swung back and forth,

to drive' the motor 50 in one direction or the other, by a connection 80 from a bellcrank 00 operated by a solenoid 92. Energization of the solenoid 92 lifts its core, thebellcrank lever 00 being weighted or spring-pressed in any desired manner to follow the upward movement of the core and close the contacts 50-60. Deenergiza-' tion of the solenoid02 allows the core to drop, rocking the bellcrank lever 00 in a direction to close the contacts 58-10.

. I00 and I08, is connected by a lead IN to the Assuming that the arm 24 is set automatically I The 'bellcrankl'ever connection 00 also acts to open and close contacts 94 forming a holding switch connected by a lead 96 and a resistance 98 to the line I2, and connected on the other side by a lead I00 to the lower end of the coil of the 5 solenoid 92. The upper end of the coil of the solenoid 02 is connected by a lead I02 to a line I04 leading from the line 56 to one contact I00 forming one of a pair of stationary contacts further described below.

The other. contact I00 of the stationary contacts is connected by a lead IIO through the resistance 90 to the line 12. A movably pivoted contact II2, arranged between the two contacts line I00 and to the lower end of the coil of the solenoid 02. r

In operation, the closing of the contacts 'I00-I I2, by means described below, closes a circult from transformer I0, through line I2, resistance 08, line H0, contacts I08-II2, lead H0, solenoid 92, lead I02, line I00, line 56, back to the transformer I0. This energizes the solenoid 92, causing lever 00 to swing in a direction to close the holding switch 00 and to close the contacts 58-60, thereby energizing the field 02 of the motor 50.

The closing of the contacts 90 establishes a holding circuit from transformer I0 by way of line I2, through resistance 00, lead 90, holding switch 90, lead I00, solenoid 92, lead I02, line I00,

' and line 55, backto the transformer I0. Thus even if contacts I08-II2 should reopen, the solenoid 92 remains energized and the contacts 50-00 remain closed.

Now if the contact H2 moves away from the contact I00, and engages the contact I00, it short-circuits solenoid 92 through the line H0, contacts H2406, line I00, and lead I02. This short-circuit de-energizes the solenoid 92, allowing the core to drop, thereby rocking the lever 00 in a direction to open the. contacts 00 and 58-00, and to close the contacts 50-70, thereby establishing a circuit through the field 50 and causing the motor 00 to run in the opposite direction. The switch circuits are now all de-' energized, and remain so until contact II2-I00 is again established.

Thus it will be seen that rocking the contact I I2 back and forth causes the motor 00 to run alternately in opposite directions, and causes the shaft 30 to oscillate as previously explained.

The contacts I00 and I00 are mounted on the opposite walls of a boxlike device I20 carried by a sleeve I22 journaled on a stationary supporting shaft I20 and rigid with an operating arm or cam I20. The cam surface of arm I26 isoperatively engaged by a roller I28 carried by the lower end of a lever I30 fulcrumed at I32 and rocked, against the resistance of a spring I00, by an edge cam I36 rigidly mounted on the end of the shaft 00 and engaging a'cam roller I38 on the lever I30. The cam I36 is oscillated as the motor 50 reverses to rock the lever I30 and is generally spiral to give the lever I00 a substantially uni form movement.

Thus as the shaft 38 oscillates back and forth, it rocks the device I20 up and down, the exact motion being determinedj by'the shape of the cam surface on the arm I20. t I

As long as the device I20 is moving freely upwardly, the contacts I00I I2 remain closed, with the corresponding motor circuit closed. The coning to close the contacts I 06-I I 2 and having at its end a pin I 44 riding in a slot I46 in the upper end of a vertical link I48.

The lower end of the link I48 is pivoted to the center of an equalizer bar I50 having at its ends rollers I52 and I54 engaged on the bottom and top respectively by arms I56 and I58 operatively connected to two spirally-wound identical fiat hollow tubes I60 and I62, of the Bourdon type, which are connected by conduits I64 and I66 to bulbs (not shown) inserted in the fluid stream at the points where the temperature is to be measured. The bulbs and the conduits I64 and I66 and the tubes I60 and I62 are all filled, in the usual manner, with mercury or other operating fluid.

It will be noted that simultaneous rise or fall of temperature at the two points being measured will merely rock the equalizer bar I50 about its center pivot, without affecting the position of the link I 48. A differential change in temperature,

however, will raise or lower the center of the bar I50, and correspondingly raise or lower the link I48 and its slot I46. I

The equalizer bar I50 is guided by a distance arm I68 connected at one end to the pivot connecting the equalizer bar I50 and the link I48, and fulcrumed at its other end on a fixed pivot I10. Arm I68 may if desired be provided with a sleeve "2 or the like, carrying a pointer (not shown) moving over a suitable scale to give a visual indication of the differential temperature measured by the above-described apparatus. A spring I14 may be provided to hold the rollers I 52 and I54 against the arms I56 and I58.

Figures 4 and illustrate the manner in which the above-described mechanism acts to control the movable contact II2. Figure 4 shows in full lines the position of the parts when the device I20 is in its uppermost position, with the arm I42 rocked byengagement of the pin I44 with the top of the slot I46, in such a manner as-to close the contacts I08-II2. As previously explained, this reverses the motor, and the device I20 begins to swing downward again, breaking the contacts I08-I I2 apart.

However, because of the holding circuit through the switch 94, the motor continues to run in the same direction until the contacts I06-I I2 reengage; this breaks the holding circuit and reverses the motor again. Thus the motor runs continuously, for short intervals in opposite directions, to oscillate the shaft 38 about a neutral position determined by the position of the link If the temperature differential changes in a direction to lift the equalizer bar to the dotted line position in Figure 4, the parts assume the positions shown in Figure 5. Now the motor will run longer than before, until pin I44 again reaches the top of slot I46, thus establishing a new range of oscillation for shaft 38, and setting the wiper 26 accordingly.

Conversely, lowering the equalizer bar I50 will pull down on the arm I42 and keep the contacts I08-II2 closed longer than usual, shifting the range of oscillation of shaft 38 in the opposite direction from that described above, and shifting the wiper 26 in the opposite direction to its corresponding new setting. 1

Different shapes of cams, shown at I26 I26, and I26 in Figures 9, 10, and 11, may be provided for difierent temperature ranges. Those illustrated are for ranges of 40 F., 20 F., and

F.. respectively, and the one in Figure 8 is for a range of 30 F. As shown, these cams are all designed to be used with the same cam I36.

Other devices may be substituted for the tubes I60 and I62 where other control conditions than a diflferential temperature are to be measured. An arm I80 of a hollow helix I82, described more fully in Spitzglass Patent No. 2,008,970, or a bellcrank I84 actuated by a metal bellows I86, may be directly connected to the link. I48 where a single temperature or pressure is the condition being measured.

While the various parts of the circuits, and of the apparatus, have been described in detail, it is not my intention to limit the scope of the invention by that description, or otherwise than by the terms of the appended claims.

I claim:

1. Apparatus" of the class described comprising an indicator, a flow-meter, a variable impedance, and a source of electric power, all arranged in series in a circuit, and a second circuit which also includes said source and which is in parallel with the first circuit and which includes a reversible motor arranged to operate the variable impedance and a reversing-switch .device controlling the motor and a mechanism which is responsive to a condition to be integrated with the flow measured by the flow-meter and which automatically controls said switch device to set .the variable impedance in accordance with said condition.

2. Apparatus of the class described comprising an indicator, a flow-meter, and a variable impedance all arranged in series in a circuit, and

a second circuit which includes a. reversible motorpedance in accordance with said condition.

3. Apparatus of the class described including a. variable impedance, and means for automatically changing the setting of said impedance comprisinga reversible motor connected to operate said impedance, a reversing switch controlling said motor, limit switches controlled by said impedance for stopping said motor when the impedance reaches either of two extreme positions, a device responsive to a condition which it is desired should control said impedance, and means operated by said device for actuating said reversing switch for changing the setting of said -im pedance in accordance with changes in said con dition.

4. Apparatus of-the class described including a variable impedance, and means for automatically changing the setting of said impedance comprising a continuously-running reversible motor connected to operate said impedance, a reversing switch controlling said motor, a device responsive to a condition which it is desired should control said impedance and which includes a part whose position is determined by measurements of said condition, and mechanism driven bysaid motor and constantly approaching and I variable impedance, and means for automatically changing the setting of said impedance according to a condition and which means comprises a -device responsive to said condition, a vertical link up and down by operation of said motor in oppo-v site directions and which includes a part in said slot and connections therefrom for reversing said switch each time said part reaches or recedes from the end of the slot.

6. Apparatus of the class described including a variable impedance, and means for automatically changing the setting of said impedance according to a condition and which means comprises a device responsive to said condition, a part whose position is varied by said device according to the effects of said condition, a reversible motor connected to operate said impedance, areversing switch controlling said motor, and a control for the reversing switch mounted to be rocked by operation of said motor in opposite directions and which includes a part engageable with the variably-positioned part and connections therefrom for reversing said switch each time said parts con tact or recede from. each other.

7. Apparatus of the class described comprising a reversible motor, a reversing switch and a holding switch having a solenoid arranged to actuate them and with the reversing switch connected to that engagement of the movable contact with one of the fixed contacts causes operation of the solenoid .to close the reversing switch in one direction and to close the holding switch to keep it so closed while engagement of the movable contact with the other fixed contact causes operation of the solenoid to open the holding switch and close the reversing switch in the opposite direction, variably-positioned .means for moving the movable contact back and forth between the fixed contacts as said device is shifted back and forth by the motor, and means controlled in ac-' cordance with a condition which it is desired shall control said motor and which varies the' position of said variably-positioned means.

8. Apparatus of the class described comprising a reversible motor, a reversing switch having a solenoid arranged to actuate them and with-the reversing switch connected to control the -direction of operation of the motor, and means for controlling the solenoid comprising a device shifted in opposite directions by oppositely-directed operation of the motor, a pair of fixed contacts and a movable contact between them all mounted on said device and so connected that engagement of the movable contact with one of the fixed contacts causes operation of the solenoid to close the reversing switch in one direction while engagement of the movable contact with the other fixed contact causes operation of the solenoid to close the reversing switch in the opposite direction, variably-positioned means for moving the movable contact back and forth between the fixed contacts as sald device is shifted back'and forth by themotor, and means controlled in accordance with a condition which it is desired shall control said motor and which varies the position of said variably-positioned means.

9. In apparatus of the class described having a reversible motor, control means for the motor comprising a control device having relatively movable parts, means operated by the motor to oscillate one of said parts thereby periodically to reverse the motor, and means for changing the setting of the other part thereby to change the time of reversal of the motor, said one part including a pivotally mounted devicecarrying a pair of contacts and said other part including an arm pivotally mounted on said device and carrying a contact adapted alternately to engage said, first named contacts.

. OTTO T. HANDWERK. 

